Uticaj subkliničke hipotireoze na funkciju endotela, koronarnu mikrocirkulaciju i pojavu ranih aterosklerotskih promena na karotidnim arterijama

Abstract

Uvod: Iako je poznato da tiroidni hormoni imaju značajan efekat na kardiovaskularni sistem, uticaj blage tiroidne disfunkcije u pravcu subkliničke hipotireoze na funkcionalne kardiovaskularne promene i dalje je otvoreno pitanje. Ispitivali smo povezanost promene u tiroidnoj funkciji u pravcu subkliničke hipotireoze sa mikrovaskularnom disfunkcijom i ranim aterosklerotskim promenama na krvnim sudovima. Metodologija: istraživanje je uključilo je 78 ispitanika sa subkliničkom hipotireozom i 55 ispitanika sa urednom tiroidnom funkcijom. Određeni su tiroidni hormonski status, antropometrijski i metabolički parametri. Merene su i izračunate protokom posredovana dilatacija (PPD), debljina intima-medija kompleksa (IMK) i koronarna rezerva protoka (KRP). Rezultati: vrednosti PPD, debljina IMK i KRP se nisu značajno razlikovale među grupama i nije bilo povezanosti PPD, debljine IMK i KRP sa tiroidnim hormonskim statusom. Kod osoba sa subkliničkom hipotireozom, ali ne i kod eutiroidnih osoba nađena je značajna povezanost debljine IMK sa indeksom telesne mase, vrednostima glikemije, HOMA IR i fT4 i značajna povezanost KRP sa sa odnosom struka i kukova, hipertenzijom, pušenjem, markerima glikoregulacije, holesterolom, LDL-holesterolom i trigliceridima. Zaključak: Zaključili smo da postoji različit uticaj klasičnih kardiovaskularnih faktora rizika na debljinu IMK i KRP kod osoba sa subkliničkom hipotireozom u poređenju sa eutiroidnim osobama i da se ove dve grupe različito ponašaju u istim okolnostima, pod istim faktorima rizika. Osnova za ovu razliku bi mogla biti izmenjen „set point“ hipotalamo-hipofizno-tiroidne osovine koji menja osetljivost mikrovaskulature kod osoba sa subkliničkom hipotireozom na poznate faktore rizika u pravcu koji je proaterogen i čini ih podložnijim za hroničnu inflamaciju niskog stepena.

Background: Although thyroid hormones have significant effect on cardiovascular system, the impact of subtle thyroid dysfunction such as subclinical hypothyroidism remains to be determined. We investigated possible association of microvascular dysfunction and early atherosclerotic changes with subclinical hypothyroidism. Methods: 78 subjects with subclinical hypothyroidism and 55 control subjects with normal serum thyroid hormonal status were included in the study. TSH, free thyroxine, free triiodothyronine, glucose, insulin, HbA1c, cholesterol, triglyceride and C-reactive protein were measured. Flow mediated dilatation (FMD), intima-media thickness (IMT) and coronary flow reserve were measured and calculated. Results: FMD, IMT and CFR were not significantly different between the two groups. and there was no association of FMD, IMT and CFR with thyroid hormonal status. In subjects with subclinical hypothyroidism, but not in euthyroid subjects, a significant association between IMT and body mass index, glycemia, HOMA IR and fT4 and a significant association between CFR and waist-hip ratio, hypertension, smoking, markers of glycoregulation, cholesterol, LDL-cholesterol and triglycerides was found. Conclusion: We concluded that there is a different impact of cardiovascular risk factors on IMT and CFR in subjects with subclinical hypothyroidism compared with euthyroid subjects and that these two groups behave differently in the same circumstances, under the same risk factors. The basis for this difference could be a modified "set point" of the hypothalamicpituitary- thyroid axis, which changes the sensitivity of the microvasculature in people with subclinical hypothyroidism to known risk factors in the direction that is proaterogenic and makes them more susceptible to low-grade chronic inflammation